This invention relates to a cloth winding device for a circular knitting machine, and more particularly to a winding device which can be conveniently and simply operated to adjust the rotation speed of the roller on which the cloth is wound so that the cloth has an even tightness, and a uniform thread distance and yard weight.
To knit cloths different in tightness and yard weight by a conventional circular knitting machine, the rotation speed of the roller on which the cloth is wound must be adjusted correspondingly. This is usually done by the use of stepless speed-changing means or by replacing the relevant gears manually. However, these ways of adjusting the rotation speed of the roller involve drawbacks described hereinafter.
As to the use of stepless speed-changing means for adjusting the rotation speed of the roller on which the cloth is wound in a conventional circular knitting machine, the tightness of the produced cloth is often uneven due to the slippage of the belts in the transmission system of the machine. Moreover, to produce cloths different in yard weight, it is necessary to perform the cloth production and then weigh the resulting product until the cloth having a correct yard weight can be obtained. This is quite labor consuming. Furthermore, the quality of the cloth obtained by this way is relatively unsteady.
As to the use of the conventional speed changing gears, although a relatively positive and good knitting effect can be achieved by this way, it is time and labor consuming to replace the original gears with those of different transmission ratio in order that the machine can produce a cloth having a specific thread distance and yard weight due to the fact that a lot of times of gear replacing and alignment by manual operation are usually needed before a desired transmission ratio can be obtained. In addition, the knitted cloth is apt to be dirtied upon in replacing the gears manually.
Another disadvantage which often occurs in changing the speed of the roller by either of the conventional ways, i.e., a cloth of nonuniform thread distance and of an uneven yard weight is formed in the same cloth batch (roll) due to nonuniform transmission ratio or an impositive transmission. In even worse cases, the knitting needles are worn seriously due to the uneven tightness of the cloth, and therefore the lives thereof will be significantly shortened.
Moreover, when the production of the cloth has been finished, it is usually required to roll up the cloth onto the respective rotating roller whose rotating speed has been chosen according to the desired yard weight and thread distance of the cloth so that the roller can roll up the cloth at that speed.
However, upon rolling up the cloth, the diameter of the cloth roll is increasing, i.e., the cloth roll is becoming bigger and bigger. In the meantime, the roller keeps at a constant speed. Those facts consequently result in an uneven tightness in the cloth roll.
The primary cause of this undesired result is in that the tension effected by the cloth roll to the cloth is relatively higher and the cloth is rolled up in a higher tightness when the cloth roll is smaller. In contrast, the tension effected to the cloth is lower when the cloth roll is bigger. This results in the outer layers of the cloth roll having a lower tightness and inner layers of a higher tightness.
Such a cloth roll having different tightness in outer and inner layers will have different yard weights in outer and inner layers. Moreover, in knitting striped cloth, the outer layer cloth and the inner layer cloth will have a different stripe distance. According to the inventor's experience, the difference between the stripe distances at two ends of a yard of striped cloth can be up to a half inch. This will result in an undesired cloth quality.
Furthermore, although the winding roller of a conventional knitting machine is provided with a manual tightness-adjusting means, an excessive tightness in the cloth often occurs and consequently it is hard to disengage the winding roller with the cloth roll after the tightness-adjusting means is initially adjusted to prevent a inadequate final tightness in the cloth roll. However, after if the tightness-adjusting means is adjusted to prevent the excessive tightness, the cloth occasionally cannot be rolled up properly or even will drop down to be squeezed between the bottom gears. In the latter case, the whole cloth winder can be damaged.